src/common/sprompt.c

   1 /*-------------------------------------------------------------------------
   2  *
   3  * sprompt.c
   4  *        simple_prompt() routine
   5  *
   6  * Portions Copyright (c) 1996-2023, PostgreSQL Global Development Group
   7  * Portions Copyright (c) 1994, Regents of the University of California
   8  *
   9  *
  10  * IDENTIFICATION
  11  *        src/common/sprompt.c
  12  *
  13  *-------------------------------------------------------------------------
  14  */
  15 #include "c.h"
  16
  17 #include "common/fe_memutils.h"
  18 #include "common/string.h"
  19
  20 #ifdef HAVE_TERMIOS_H
  21 #include <termios.h>
  22 #endif
  23
  24
  25 /*
  26  * simple_prompt
  27  *
  28  * Generalized function especially intended for reading in usernames and
  29  * passwords interactively.  Reads from /dev/tty or stdin/stderr.
  30  *
  31  * prompt:              The prompt to print, or NULL if none (automatically localized)
  32  * echo:                Set to false if you want to hide what is entered (for passwords)
  33  *
  34  * The input (without trailing newline) is returned as a malloc'd string.
  35  * Caller is responsible for freeing it when done.
  36  */
  37 char *
  38 simple_prompt(const char *prompt, bool echo)
  39 {
  40         return simple_prompt_extended(prompt, echo, NULL);
  41 }
  42
  43 /*
  44  * simple_prompt_extended
  45  *
  46  * This is the same as simple_prompt(), except that prompt_ctx can
  47  * optionally be provided to allow this function to be canceled via an
  48  * existing SIGINT signal handler that will longjmp to the specified place
  49  * only when *(prompt_ctx->enabled) is true.  If canceled, this function
  50  * returns an empty string, and prompt_ctx->canceled is set to true.
  51  */
  52 char *
  53 simple_prompt_extended(const char *prompt, bool echo,
  54                                            PromptInterruptContext *prompt_ctx)
  55 {
  56         char       *result;
  57         FILE       *termin,
  58                            *termout;
  59 #if defined(HAVE_TERMIOS_H)
  60         struct termios t_orig,
  61                                 t;
  62 #elif defined(WIN32)
  63         HANDLE          t = NULL;
  64         DWORD           t_orig = 0;
  65 #endif
  66
  67 #ifdef WIN32
  68
  69         /*
  70          * A Windows console has an "input code page" and an "output code page";
  71          * these usually match each other, but they rarely match the "Windows ANSI
  72          * code page" defined at system boot and expected of "char *" arguments to
  73          * Windows API functions.  The Microsoft CRT write() implementation
  74          * automatically converts text between these code pages when writing to a
  75          * console.  To identify such file descriptors, it calls GetConsoleMode()
  76          * on the underlying HANDLE, which in turn requires GENERIC_READ access on
  77          * the HANDLE.  Opening termout in mode "w+" allows that detection to
  78          * succeed.  Otherwise, write() would not recognize the descriptor as a
  79          * console, and non-ASCII characters would display incorrectly.
  80          *
  81          * XXX fgets() still receives text in the console's input code page.  This
  82          * makes non-ASCII credentials unportable.
  83          *
  84          * Unintuitively, we also open termin in mode "w+", even though we only
  85          * read it; that's needed for SetConsoleMode() to succeed.
  86          */
  87         termin = fopen("CONIN$", "w+");
  88         termout = fopen("CONOUT$", "w+");
  89 #else
  90
  91         /*
  92          * Do not try to collapse these into one "w+" mode file. Doesn't work on
  93          * some platforms (eg, HPUX 10.20).
  94          */
  95         termin = fopen("/dev/tty", "r");
  96         termout = fopen("/dev/tty", "w");
  97 #endif
  98         if (!termin || !termout
  99 #ifdef WIN32
 100
 101         /*
 102          * Direct console I/O does not work from the MSYS 1.0.10 console.  Writes
 103          * reach nowhere user-visible; reads block indefinitely.  XXX This affects
 104          * most Windows terminal environments, including rxvt, mintty, Cygwin
 105          * xterm, Cygwin sshd, and PowerShell ISE.  Switch to a more-generic test.
 106          */
 107                 || (getenv("OSTYPE") && strcmp(getenv("OSTYPE"), "msys") == 0)
 108 #endif
 109                 )
 110         {
 111                 if (termin)
 112                         fclose(termin);
 113                 if (termout)
 114                         fclose(termout);
 115                 termin = stdin;
 116                 termout = stderr;
 117         }
 118
 119         if (!echo)
 120         {
 121 #if defined(HAVE_TERMIOS_H)
 122                 /* disable echo via tcgetattr/tcsetattr */
 123                 tcgetattr(fileno(termin), &t);
 124                 t_orig = t;
 125                 t.c_lflag &= ~ECHO;
 126                 tcsetattr(fileno(termin), TCSAFLUSH, &t);
 127 #elif defined(WIN32)
 128                 /* need the file's HANDLE to turn echo off */
 129                 t = (HANDLE) _get_osfhandle(_fileno(termin));
 130
 131                 /* save the old configuration first */
 132                 GetConsoleMode(t, &t_orig);
 133
 134                 /* set to the new mode */
 135                 SetConsoleMode(t, ENABLE_LINE_INPUT | ENABLE_PROCESSED_INPUT);
 136 #endif
 137         }
 138
 139         if (prompt)
 140         {
 141                 fputs(_(prompt), termout);
 142                 fflush(termout);
 143         }
 144
 145         result = pg_get_line(termin, prompt_ctx);
 146
 147         /* If we failed to read anything, just return an empty string */
 148         if (result == NULL)
 149                 result = pg_strdup("");
 150
 151         /* strip trailing newline, including \r in case we're on Windows */
 152         (void) pg_strip_crlf(result);
 153
 154         if (!echo)
 155         {
 156                 /* restore previous echo behavior, then echo \n */
 157 #if defined(HAVE_TERMIOS_H)
 158                 tcsetattr(fileno(termin), TCSAFLUSH, &t_orig);
 159                 fputs("\n", termout);
 160                 fflush(termout);
 161 #elif defined(WIN32)
 162                 SetConsoleMode(t, t_orig);
 163                 fputs("\n", termout);
 164                 fflush(termout);
 165 #endif
 166         }
 167         else if (prompt_ctx && prompt_ctx->canceled)
 168         {
 169                 /* also echo \n if prompt was canceled */
 170                 fputs("\n", termout);
 171                 fflush(termout);
 172         }
 173
 174         if (termin != stdin)
 175         {
 176                 fclose(termin);
 177                 fclose(termout);
 178         }
 179
 180         return result;
 181 }